Thanks for your understanding, Breaking Dawn.
I know these situations can rapidly escalate, so I kept it calm and rational and to the point. But as I was walking home, I found I was involuntarily shaking my head.
We seem to have lucked-out with our newest neighbours who just moved into the house between ours and the disruptive, selfish people. These new folks were so considerate, and had their move so well-planned, that we never even heard them moving in. Which is really quite something, because our houses are small and are really only a few yards apart. I would hate to see their new little dream home become a source of unwelcome noise and stress for them.